OK - having a look Love Story definitely appears to be a romance. And given comments like "...this is the book that defined a generation..." I think it's probably a really good choice.
Some others there look like monster books which I might have voted for if they were more closely aligned with my current reading plans. I just can't devote that much time to Binchy or Gabaldon. Even Chadwick is pushing it - although the content looks quite a bit more interesting to me so I could possibly make an exception. I'm noting that author down as a TBR for historical fiction.
Strangely enough, although I had a strong aversion to Shards of Honour initially because I thought it was an excuse to nominate Science Fiction, I'm reconsidering after reading a few descriptions of the book. It seems the romance is very central to the storyline and quite a few write-ups refer to it as a sci-fi romance. Given that I'm curious about Bujold anyway, I think that will get a vote from me.
So I think I've ended up with a nice list:
Portrait of Jenny, Lolita, Shards of Honour, Water for Elephants, A Town Like Alice, and Love Story.
I think I'd be quite happy to find room in my reading schedule for any of those. In fact, thanks to these nominations I'm adding a couple of these to my TBR anyway.